[ZendTo] Support for custom mail headers

[Michael Young]

On Fri, 25 Aug 2023, Julian Field via ZendTo wrote:

> Hi Adam,
> 
> That sounds a great idea. Didn't know you could make O365 do that.
> 
> I've added it as a new setting at the bottom of the SMTP* settings, called
> "SMTPextraHeaders". It's just a simple array of strings as you suggest.
> 
> It will be in the next release (which I'm actually working on!!).

There is a minor typo in the example for this in preferences.php in 
6.14-2 Beta as
   // 'SMTPextraHeaders => array('X-Auto-Response-Suppress: All'),
should be
   // 'SMTPextraHeaders' => array('X-Auto-Response-Suppress: All'),

 	Michael Young